This invention relates to a novel variety of navel orange tree. The invention is characterized by relative late maturity of its fruit in comparison with other known late navel varieties, such as the Lane Late navel varieties. The varietal information as it relates to taxonomically important seasonal information was determined for Australia which is in the southern hemisphere. All time periods remain essentially unchanged in the northern hemisphere, but the time frame is shifted by approximately six months. Therefore, activities in April or May would correspond in the U.S. to activities in October or November.
The plant is of unknown parentage and was found as a young tree in an orchard of valencia orange trees in Nangiloc in Victoria, Australia in 1987. Although the plant flowered at the same time as other navel oranges, the fruit matured later than any of the other commercially available varieties including Lane Late. The plant maximally flowers in mid October and provides mature fruit from November to February. The typical navel orange matures in September and October and late varieties mature in November and December. Wiffen Summer Navel is the first variety to our knowledge that will meaningfully extend the navel season into February. Navel oranges are a significant fresh fruit crop and there are economic advantages to extending its availability to consumers.
The variety Lane Late is believed to be the variety which is closest to Wiffen Summer Navel in phenotype. However, Wiffen Summer Navel differs from Lane Late in three important characteristics. The Wiffen Summer Navel fruits mature later, the total soluble solids of mature Wiffen Summer Navel fruit is greater (better flavor) and the Wiffen Summer Navel fruit are smaller. In side-by-side trials against late hanging varieties, Rohde Summer Navel (U.S. Plant Pat. No. 7,651), Powell (U.S. Plant Pat. No. 6,733), Summer Gold, Hutton, Christensen and Autumn Gold, Wiffen Summer Navel has the highest total solids, the highest acid content, and smallest average size (see Gallasch, P. T., Int'l Citrus Congress, May 1996, The Proceedings of the International Society of Citriculture (In Press)). In all other regards, The Wiffen Summer Navel variety falls within the standards for commercially acceptable navel oranges.
Wiffen Summer Navel has been asexually reproduced by grafting trees 11 and 16 and has been determined to be stable. The following data was taken from two eight year old plants which have been grafted onto a sweet orange interstock and rootstock (Citrange). The location was Victoria, Australia, at the Sunraysia Horticulture Centre.